U.S. patent number 10,703,961 [Application Number 15/228,490] was granted by the patent office on 2020-07-07 for phosphorus functional inversion agents for water-in-oil latices and methods of use.
This patent grant is currently assigned to Ecolab USA Inc.. The grantee listed for this patent is Ecolab USA Inc.. Invention is credited to Xiaojin Harry Li, Anand Parthasarathy.
United States Patent |
10,703,961 |
Li , et al. |
July 7, 2020 |
Phosphorus functional inversion agents for water-in-oil latices and
methods of use
Abstract
Water-in-oil lattices of water soluble or dispersible polymers
and methods of using the same are presented. The lattices include
phosphorus functional inversion agents that provide rapid and
complete inversion of the lattices under conditions wherein the
water source used to invert the latex is provided at high
temperature, or includes a high level of total dissolved solids, or
is both high temperature and high total dissolved solids.
Inventors: |
Li; Xiaojin Harry (Palatine,
IL), Parthasarathy; Anand (Naperville, IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Ecolab USA Inc. |
St. Paul |
MN |
US |
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Assignee: |
Ecolab USA Inc. (St. Paul,
MN)
|
Family
ID: |
57984640 |
Appl.
No.: |
15/228,490 |
Filed: |
August 4, 2016 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170037300 A1 |
Feb 9, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62202199 |
Aug 7, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09K
8/588 (20130101); C08F 2/32 (20130101); C08F
2/44 (20130101); C08F 2/22 (20130101); C09K
8/584 (20130101); E21B 43/20 (20130101); C08F
2/26 (20130101); C08F 220/56 (20130101); C08F
220/56 (20130101); C08F 220/06 (20130101) |
Current International
Class: |
C09K
8/584 (20060101); C08F 2/44 (20060101); C08F
220/56 (20060101); C08F 2/32 (20060101); C08F
2/22 (20060101); E21B 43/20 (20060101); C09K
8/588 (20060101); C08F 2/26 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2911366 |
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Nov 2014 |
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CA |
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0753827 |
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Feb 1995 |
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JP |
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09104823 |
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Apr 1997 |
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JP |
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2745642 |
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Apr 1998 |
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JP |
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2005058977 |
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Jun 2005 |
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WO |
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Other References
https://www.sigmaaldrich.com/catalog/ product/
aldrich/388858?lang=en®ion=US downloaded Dec. 4, 2018. cited
by examiner .
https://www.sigmaaldrich.com/catalog/ product/
aldrich/388858?lang=en.RTM. ion=US downloaded Dec. 4, 2018. cited
by examiner .
data sheet, N-phosphonomethyl glycine downloaded on Dec. 5, 2018.
cited by examiner .
https://www.britannica.com/science/kerosene downloaded on Dec. 5,
2018. cited by examiner .
Sunder et al, Macromolecules (1999) 32: pp. 4240-4246. cited by
applicant .
Garcia-Bernabe et al, Chem. Eur. J. (2004) 10: pp. 2822-2830. cited
by applicant .
Siegers et al, Chem. Eur. J (2004) 10: pp. 2831-2838. cited by
applicant .
Haag et al, J. Am. Chem. Soc. (2000) 122: pp. 2954-2955. cited by
applicant .
International Search Report PCT/US2016/045541, dated Nov. 8, 2016.
cited by applicant .
International Search Report PCT/US2016/045546, dated Nov. 14, 2016.
cited by applicant .
International Search Report PCT/US2016/045590, dated Nov. 20, 2016.
cited by applicant .
Written Opinion PCT/US2016/045541, dated Nov. 14, 2016. cited by
applicant .
Written Opinion PCT/US2016/045546, dated Nov. 14, 2016. cited by
applicant .
Written Opinion PCT/US2016/045590, dated Nov. 20, 2016. cited by
applicant .
Extended European Search Report in European Application No.
16835666.5, dated Feb. 14, 2019, 10 pages. cited by applicant .
Office Action in Brazilian Application No. BR112018002467-8, dated
Jan. 6, 2020, 6 pages (4 pages Official Copy, 2 pages English
Translation). cited by applicant .
Office Action (Communication pursuant to Article 94(3) EPC) in
European Application No. 16835666.5, dated Jan. 16, 2020, 6 pages.
cited by applicant .
SciFinder Results, American Chemical Society, 2019, 8 pages. cited
by applicant.
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Primary Examiner: Bhushan; Kumar R
Attorney, Agent or Firm: Kagan Binder, PLLC
Claims
The invention claimed is:
1. A water-in-oil latex comprising about 15 wt % to 70 wt % of a
water soluble or dispersible polymer comprising 1 mol % to about
100 mol % acrylamide monomers; about 0.1 wt % to 20.0 wt % of an
inversion surfactant characterized as having a
hydrophilic/lipophilic balance of 10 or greater; and about 0.1 wt %
to 20.0 wt % of a phosphorus functional inversion agent that is a
hydrotrope.
2. The latex of claim 1 comprising about 1.0 wt % to 20.0 wt % of
the inversion agent and inversion surfactant combined.
3. The latex of claim 1, wherein the phosphorus functional
inversion agent comprises a phosphorus functional compound
characterized as a water-soluble compound having at least one
phosphono moiety or at least one phosphino moiety.
4. The latex of claim 3, wherein the phosphorus functional compound
has 1 to 5 phosphono moieties.
5. The latex of claim 1, wherein the phosphorus functional
inversion agent is characterized as having a hydrophilic/lipophilic
balance of greater than about 45.
6. The latex of claim 1 comprising about 0.1 wt % to 5.0 wt % of
the phosphorus functional inversion agent.
7. The latex of claim 1 comprising about 3 wt % to 50 wt % water;
about 10 wt % to 40 wt % of a compound or blend thereof that is
less than 0.1 wt % soluble in water at 25.degree. C. and is
substantially a liquid over the range of 20.degree. C. to
90.degree. C. and comprising linear hydrocarbon moieties; about 20
wt % or less of a latex surfactant characterized as having a
hydrophilic/lipophilic balance of between 2 and 10; and about 0.1
wt % to 5.0 wt % of the inversion agent.
8. The latex of claim 1, wherein the latex is shelf stable.
9. A method of forming an invertible latex, the method comprising
(a) forming a water-in-oil latex comprising about 15 wt % to 70 wt
% of a water soluble or dispersible polymer; about 3 wt % to 50 wt
% water; about 10 wt % to 40 wt % of a compound or blend thereof
that is less than 0.1 wt % soluble in water at 25.degree. C. and is
substantially a liquid over the range of 20.degree. C. to
90.degree. C. and comprising linear, branched, or cyclic
hydrocarbon moieties; and about 20 wt % or less of a latex
surfactant characterized as having a hydrophilic/lipophilic balance
of between 2 and 10; and (b) adding to the latex about 0.1 wt % to
20.0 wt % of an inversion surfactant characterized as having a
hydrophilic/lipophilic balance of 10 or greater and about 0.1 wt %
to 5.0 wt % of a phosphorus functional inversion agent to form an
invertible latex, wherein the phosphorus functional inversion agent
is a hydrotrope.
10. The method of claim 9, wherein the invertible latex is shelf
stable.
11. The method of claim 9, wherein the phosphorus functional
inversion agent comprises a phosphorus functional compound
characterized as a water-soluble compound having at least one
phosphono moiety or at least one phosphino moiety.
12. The method of claim 9, wherein the phosphorus functional
inversion agent is characterized as having a hydrophilic/lipophilic
balance of greater than about 45.
13. A method of recovering hydrocarbon compounds from a
subterranean reservoir, the method comprising (a) forming a
water-in-oil latex comprising: about 15 wt % to 70 wt % of a water
soluble or dispersible polymer; about 3 wt % to 50 wt % water;
about 10 wt % to 40 wt % of a compound or blend thereof that is
less than 0.1 wt % soluble in water at 25.degree. C. and is
substantially a liquid over the range of 20.degree. C. to
90.degree. C. and comprising linear, branched, or cyclic
hydrocarbon moieties; and about 20 wt % or less of a latex
surfactant characterized as having a hydrophilic/lipophilic balance
of between 2 and 10; (b) adding to the latex about 0.1 wt % to 20.0
wt % of an inversion surfactant characterized as having a
hydrophilic/lipophilic balance of 10 or greater and about 0.1 wt %
to 5.0 wt % of a phosphorus functional inversion agent to form an
invertible latex, wherein the phosphorus functional inversion agent
is a hydrotrope; (c) adding a water source to the invertible latex
in a single addition to form a polymer flooding solution comprising
about 100 ppm to 10,000 ppm of the water soluble or dispersible
polymer, (d) injecting the polymer flooding solution into the
subterranean reservoir, and (e) recovering the hydrocarbon
compounds.
14. The method of claim 13, wherein the water source comprises a
temperature of about 30.degree. C. to 100.degree. C.
15. The method of claim 13, wherein the water source includes about
0.1 to 30 wt % total dissolved solids.
16. The method of claim 13, wherein the water source comprises a
temperature of about 30.degree. C. to 100.degree. C. and includes
about 0.1 to 30 wt % total dissolved solids.
Description
TECHNICAL FIELD
The invention relates to water-in-oil lattices of water dispersible
polymers and compositions that provide for rapid inversion of the
lattices when diluted.
BACKGROUND
Crude oil development and production can include up to three
distinct phases: primary, secondary, and tertiary (or enhanced)
recovery. During primary recovery, the natural pressure of the
reservoir or gravity drives oil into the wellbore, combined with
artificial lift techniques (such as pumps) which bring the oil to
the surface. But only about 10 percent of a reservoir's original
oil in place is typically produced during primary recovery.
Secondary recovery techniques extend a field's productive life
generally by injecting water or gas to displace oil and drive it to
a production wellbore, resulting in the recovery of 20 to 40
percent of the original oil in place.
Enhanced oil recovery, or EOR, is a generic term encompassing
techniques for increasing the amount of crude oil that can be
extracted from a subterranean formation such as an oil field. EOR
techniques offer prospects for ultimately producing 30 to 60
percent, or more, of the reservoir's original oil in place. Three
major categories of EOR have been found to be commercially
successful to varying degrees:
Thermal recovery is the introduction of heat such as the injection
of steam to lower the viscosity of the oil and improve its ability
to flow through the reservoir.
Gas injection is the injection of gases such as natural gas,
nitrogen, or carbon dioxide that expand in a reservoir to push
additional oil to a production wellbore, or gases that dissolve in
the oil to lower its viscosity and improve flow rate.
Chemical injection is the injection of polymer dispersions to
increase the effectiveness of waterfloods, or the use of
detergent-like surfactants to help lower the surface tension that
often prevents oil droplets from moving through a reservoir.
Chemical injection of a polymer is also referred to as polymer
flooding. This method improves the vertical and areal sweep
efficiency as a consequence of improving the water/oil mobility
ratio. In addition, the polymer reduces the contrasts in
permeability by preferentially plugging the high permeability zones
flooded. This forces the water to flood the lower permeability
zones and increases the sweep efficiency. The art in this area is
well-developed for conventional oil recovery applications.
Of these techniques, polymer flooding using water-in-oil (w/o)
latex products is particularly favored for use in offshore
reservoirs and other relatively isolated operations due to the ease
of use and relatively simple equipment requirements. Polymer
flooding is generally accomplished by dissolving the selected
polymer in water and injecting the polymer solution into the
reservoir. However, since the target concentration of polymer in
the polymer dispersions is typically about 1 wt % or less,
transport at the target concentration is not economically
efficient. Transporting the dried polymers, while economically
efficient for the supplier, is not favorable for field use due to
limited space for dry polymer make-down equipment and difficulties
in fully hydrating the polymers in the field. To address these
issues, various formulations have been developed to allow
economically feasible transportation and storage. Specialized
methods have also been developed to convert the formulations to use
concentrations of fully hydrated polymers in the field.
Organic polymers traditionally used in EOR include water soluble
polymers such as polyacrylamide homopolymers and copolymers with
acrylic acid or conjugate base thereof and/or one or more other
water soluble monomers, and hydrophobically modified water soluble
polymers, also called associative polymers or associative
thickeners. Associative thickeners are typically copolymers of
acrylamide, acrylic acid, or both with about 1 mole % or less of a
hydrophobic monomer such as a C.sub.8-C.sub.16 linear or branched
ester of acrylic acid. Any of these water soluble polymers are
deliverable as a dry powder, as a gel-like concentrate in water, or
in the water phase of a w/o latex. Of these formats, water-in-oil
lattices have the advantage of being deliverable in a liquid format
that is easily handled in the field because the latex viscosity is
lower than that of a water solution of comparable wt % polymer. The
liquid products are also easy to make down with little equipment
and a small space footprint compared to that of dry polymer
products.
Commercial w/o lattices are formulated for EOR by dissolving
monomer(s) in a high-solids aqueous solution to form a water phase
(or monomer phase), mixing one or more hydrocarbon solvents and a
surfactant or a blend thereof having a hydrophilic-lipophilic
balance (HLB) of about 2 to 10 to form an oil phase, mixing the two
phases using techniques to result in a water-in-oil emulsion or
latex, and polymerizing the monomer via a standard free-radical
initiation. The w/o latex may be a macroemulsion, nanoemulsion,
microemulsion, or combination thereof. The free radical initiation
may be radiation, photo, thermal, or redox initiation, or any
combination thereof. After polymerization is complete, a higher HLB
surfactant (HLB>10) or a blend thereof having an HLB>10 is
often added to facilitate latex inversion when water is added.
"Inversion" is a term of art to describe the dilution of w/o
lattices with a water source, causing destabilization of the latex
and subsequent dissolution of the concentrated polymer particles.
In some cases, the higher HLB surfactant is added in the field,
immediately prior to addition of water to dilute the latex; or is
added in-line with the water source used to dilute the latex. In
other cases, the higher HLB surfactant is added directly to the w/o
latex after polymerization is complete, and the latex is stable or
even shelf stable. In such cases, careful control of type and
amount of surfactant is required to provide a sufficiently stable
latex to facilitate storage and transportation, while providing for
improved inversion performance in the field.
Recently, there has arisen the need to address polymer flooding in
challenging conditions encountered in reservoirs wherein the
ambient or produced water contacted by the polymer includes high
total dissolved solids, such as a high saline or hardness content,
in some cases involving total dissolved solids of up to about 30 wt
%. In some cases the ambient or produced water is tap water, hard
water, brackish water, municipal waste water, produced water, or
seawater. Field operators strongly prefer to use such water sources
to dilute polymer flooding formulations to final use concentrations
rather than employ purified water sources. Reasons for the
preference include reducing costs by diverting some or all of the
water source already being injected into a reservoir to dilute the
polymer flooding formulations and reducing the environmental impact
associated with employing a purified water source. However, use of
such water sources leads to difficulties in dispersing the high
molecular weight polymers to use concentrations. Inversion of w/o
lattices in such water sources can result in slow inversion times
and/or the requirement of multistage dilution and mixing
procedures; it can also result in coagulation, precipitation, or
gross phase separation of polymer upon or after contact of the
latex with the diluted water environment. Thus there is a need to
address inversion of w/o lattices in field conditions where the use
water source has high total dissolved solids.
Another need in the industry is to address reservoirs where the
water source contacted by a w/o latex is at an extreme temperature,
such as 30.degree. C. to 100.degree. C. or -10.degree. C. to
10.degree. C. Extreme temperature water sources lead to
difficulties in dispersing high molecular weight, water soluble
polymers delivered in w/o lattices, similarly to the difficulties
encountered in the use of high total dissolved solids water
sources. In some cases, conditions of both extreme temperature and
high total dissolved solids are encountered in the ambient or
produced water source employed to dilute polymer flooding
formulations to use concentrations. Such conditions cause
instability of w/o lattices during inversion, evidenced by
formation of gel particles, coagulum, polymer coated out on contact
surfaces, and gross coalescence of phases (conventionally referred
to as "separation") and the like. The products of this instability
cause plugged equipment in the field, reduced reservoir
permeability, plugged formation, and ultimately failure to
accomplish mobility control within the reservoir. These problems
remain largely unaddressed by conventional formulations, methods,
and equipment developed for inversion of w/o lattices in the field.
For example, formulations described in US Patent Application
Publication No. 2014/0051620 A1, which comprise an inversion agent
such as glycerol, do not provide satisfactory performance under
conditions using water sources having high total dissolved solids,
extreme temperature, or both.
As a result, there is a substantial need in the industry to develop
technologies suitable for carrying out enhanced oil recovery in
reservoirs where high temperature water sources, high total
dissolved solids water sources, or both are used in conjunction
with EOR. There is a substantial need in the industry for w/o
polymer lattices that invert rapidly to form stable, fully hydrated
or dissolved polymer solutions at water temperatures of 30.degree.
C. to 100.degree. C. There is a substantial need in the industry
for w/o polymer lattices that invert rapidly to form stable, fully
hydrated or dissolved polymer solutions using water sources having
up to 30 wt % total dissolved solids. There is a substantial need
in the industry for w/o polymer lattices that invert rapidly to
form stable, fully hydrated or dissolved polymer solutions at
polymer concentrations of 1 wt % or less using water sources having
high total dissolved solids, high temperature, or both.
SUMMARY
Described herein are water-in-oil (w/o) lattices. The lattices are
formed by combining about 0.1 wt % to 20.0 wt % of a phosphorus
functional inversion agent with about 15 wt % to 70 wt % of a water
soluble or dispersible polymer comprising 1 mol % to about 100 mol
% acrylamide monomers; and about 0.1 wt % to 20.0 wt % of an
inversion surfactant having a hydrophilic/lipophilic balance of 10
or greater. In some embodiments, the w/o latex comprises about 0.1
wt % to 5.0 wt % of a phosphorus functional inversion agent that is
a hydrotrope; about 15 wt % to 70 wt % of the water soluble
polymer; about 0.1 wt % to 20.0 wt % of the inversion surfactant;
about 3 wt % to 50 wt % water; about 10 wt % to 40 wt % of a
compound or blend thereof that is less than 0.1 wt % soluble in
water at 25.degree. C. and is substantially a liquid over the range
of 20.degree. C. to 90.degree. C. and comprising linear, branched,
or cyclic hydrocarbon moieties; and about 20 wt % or less of a
latex surfactant characterized as having a hydrophilic/lipophilic
balance of between 2 and 10.
Also described herein is a method of forming an invertible latex,
the method comprising a) forming a water-in-oil latex comprising
about 15 wt % to 70 wt % of a water soluble or dispersible polymer;
about 3 wt % to 50 wt % water; about 10 wt % to 40 wt % of a
compound or blend thereof that is less than 0.1 wt % soluble in
water at 25.degree. C. and is substantially a liquid over the range
of 20.degree. C. to 90.degree. C. and comprising linear, branched,
or cyclic hydrocarbon moieties; and about 20 wt % or less of a
latex surfactant characterized as having a hydrophilic/lipophilic
balance of between 2 and 10; and b) adding to the latex about 0.1
wt % to 20.0 wt % of an inversion surfactant characterized as
having a hydrophilic/lipophilic balance of 10 or greater and about
0.1 wt % to 5.0 wt % of a phosphorus functional inversion agent to
form an invertible latex.
Also described herein is a method of recovering hydrocarbon
compounds from a subterranean reservoir, the method comprising a)
forming an invertible latex comprising about 15 wt % to 70 wt % of
a water soluble or dispersible polymer, about 3 wt % to 50 wt %
water, about 10 wt % to 40 wt % of a compound or blend thereof that
is less than 0.1 wt % soluble in water at 25.degree. C. and is
substantially a liquid over the range of 20.degree. C. to
90.degree. C. and comprising linear, branched, or cyclic
hydrocarbon moieties, and about 20 wt % or less of a latex
surfactant characterized as having a hydrophilic/lipophilic balance
of between 2 and 10; and adding to the latex about 0.1 wt % to 20.0
wt % of an inversion surfactant characterized as having a
hydrophilic/lipophilic balance of 10 or greater and about 0.1 wt %
to 5.0 wt % of a phosphorus functional inversion agent; b) adding a
water source to the invertible latex in a single addition to form a
polymer flooding solution comprising about 100 ppm to 10,000 ppm of
the water soluble or dispersible polymer; c) injecting the polymer
flooding solution into the subterranean reservoir; and d)
recovering the hydrocarbon compounds.
Additional advantages and novel features of the invention will be
set forth in part in the description that follows, and in part will
become apparent to those skilled in the art upon examination of the
following, or may be learned through routine experimentation upon
practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a line graph of torque monitor data at 60.degree. C.
showing the invertibility of w/o lattices comprising 3 wt % of a
phosphorus functional inversion agent and 3.3% of TDA-12 as an
inverting surfactant ([polymer]=10000 ppm in 3.5% SSW).
DETAILED DESCRIPTION
Although the present disclosure provides references to preferred
embodiments, persons skilled in the art will recognize that changes
may be made in form and detail without departing from the spirit
and scope of the invention. Various embodiments will be described
in detail with reference to the drawings. Reference to various
embodiments does not limit the scope of the claims attached hereto.
Additionally, any examples set forth in this specification are not
intended to be limiting and merely set forth some of the many
possible embodiments for the appended claims.
Definitions
As used herein, the term "polymer" means a water soluble or water
dispersible polymer. The term "polymer" encompasses and includes
homopolymers, copolymers, terpolymers and polymers with more than 3
monomers, crosslinked or partially crosslinked polymers, and
combinations or blends of these.
The term "monomer" is used in context to mean an ethylenically
unsaturated polymerizable compound or the polymerized residue
thereof. As used herein, the term "anionic monomer" means an
unsaturated compound or polymerized residue thereof bearing an
acidic group, or a salt thereof. As used herein, the term "cationic
monomer" means an unsaturated compound or polymerized residue
thereof bearing a positive charge, or a salt thereof.
As used herein, the term "polymer solution" or "polymer dispersion"
means a polymer composition substantially dispersed or dissolved in
water, a water source, or a water-based solution. The polymer
solution is a solution as formed, or in the case of some EOR
applications the solution before injection, during injection, or
after injection as determined by context. Water-based solutions
include one or more dissolved salts, buffers, acids, bases,
surfactants, or other dissolved, dispersed, or emulsified
compounds, materials, components, or combinations thereof.
As used herein, the term "water source" means a source of water
comprising, consisting essentially of, or consisting of fresh
water, deionized water, distilled water, produced water, municipal
water, waste water such as runoff water or municipal waste water,
treated or partially treated waste water, well water, brackish
water, "gray water", sea water, or a combination of two or more
such water sources as determined by context. In some embodiments, a
water source includes one or more salts, ions, buffers, acids,
bases, surfactants, or other dissolved, dispersed, or emulsified
compounds, materials, components, or combinations thereof. In some
embodiments, a water source includes about 0 wt % to 30 wt % total
dissolved solids. Generally and as determined by context, the term
"water source" includes high total dissolved solids water sources,
high temperature water sources, and water sources that are both
high total dissolved solids and high temperature water sources.
As used herein, the term "high temperature" means about 30.degree.
C. to 100.degree. C., as specified or determined by context.
As used herein, the term "high total dissolved solids" refers to a
water source having at least 1 wt % non-polymeric solids dissolved
therein, and in embodiments up to about 30 wt % non-polymeric
solids dissolved therein. In general, "saline" or "salinity" refers
to a water source wherein a portion, in some embodiments a
substantial portion, of the total dissolved solids are salts, as
determined by context.
As used herein, the terms "water-in-oil latex" or "w/o latex" mean
a discontinuous internal water phase within a continuous oil phase,
wherein the water phase includes at least one monomer or polymer.
In general and as determined by context, these terms denote a latex
prior to addition of inverting surfactants.
As used herein, the term "oil" or "hydrocarbon solvent" as applied
to an oil phase of a water-in-oil latex, means any compound or
blend thereof that is less than 0.1 wt % soluble in water at
25.degree. C., is substantially chemically inert within a w/o latex
as described herein, and is a liquid over at least the range of
20.degree. C. to 100.degree. C.
As used herein, the term "water phase" means a water source having
at least a monomer or polymer dispersed or dissolved therein,
further wherein the dispersion or solution is a discontinuous phase
within a w/o latex.
As used herein, the term "stable" as applied to a latex or emulsion
means a kinetically stable latex or emulsion that absent any force
applied, temperature change, or chemical added to a latex, the
latex is or is capable of being substantially free of coagulation,
plating out, precipitation, gross coalescence of phases
(conventionally referred to as "separation") or any other evidence
of instability conventionally associated with water-in-oil lattices
for at least about 24 hours at about 20.degree. C. As used herein,
the term "shelf stable" means stable for at least 2 months. As used
herein, the term "freeze-thaw stable" means stable after at least 1
freeze-thaw cycle.
As used herein, the term "invertible latex" means a w/o latex
additionally including at least one inversion surfactant and at
least one inversion agent, the inversion agent comprising at least
one phosphorus functional compound.
As used herein, the term "invert" or "inversion" as applied to the
w/o lattices of the invention means to contact an invertible latex
with a water source in an amount sufficient to form a polymer
flooding solution.
As used herein, the term "polymer flooding solution" or "polymer
solution" means a polymer solution or dispersion of about 100 ppm
(0.01 wt %) to 10,000 ppm (1.00 wt %) resulting from the inversion
of an invertible latex.
As used herein, the term "single component" as applied to the w/o
lattices of the invention means that at least one inversion
surfactant and at least one inversion agent are added to an
existing w/o latex and the combination is shelf stable. The term is
used in contrast to inversion surfactants or other compounds added
in-line during injection and inversion.
As used herein, the term "optional" or "optionally" means that the
subsequently described component, event or circumstance may be, but
need not be present or occur. The description therefore discloses
and includes instances in which the event or circumstance occurs
and instances in which it does not, or instances in which the
described component is present and instances in which it is
not.
As used herein, the term "about" modifying, for example, the
quantity of an ingredient in a composition, concentration, volume,
temperature, time, yield, flow rate, pressure, and like values, and
ranges thereof, employed in describing the embodiments of the
disclosure, refers to variation in the numerical quantity that can
occur, for example, through typical measuring and handling
procedures used for making compounds, compositions, concentrates or
use formulations; through inadvertent error in these procedures;
through differences in the manufacture, source, or purity of
starting materials or ingredients used to carry out the methods,
through standard operating machine error, and like proximate
considerations. The term "about" also encompasses amounts that
differ due to aging of a formulation with a particular initial
concentration or mixture, and amounts that differ due to mixing or
processing a formulation with a particular initial concentration or
mixture. Where modified by the term "about" the claims appended
hereto include equivalents according to this definition.
As used herein, the term "substantially" means "consisting
essentially of", as that term is construed in U.S. patent law, and
includes "consisting of" as that term is construed in U.S. patent
law. For example, a solution that is "substantially free" of a
specified compound or material may be free of that compound or
material, or may have a minor amount of that compound or material
present, such as through unintended contamination or incomplete
purification. A "minor amount" may be a trace, an unmeasurable
amount, an amount that does not interfere with a value or property,
or some other amount as provided in context. A composition that has
"substantially only" a provided list of components may consist of
only those components, or have a trace amount of some other
component present, or have one or more additional components that
do not materially affect the properties of the composition.
Additionally, "substantially" modifying, for example, the type or
quantity of an ingredient in a composition, a property, a
measurable quantity, a method, a value, or a range, employed in
describing the embodiments of the disclosure, refers to a variation
that does not affect the overall recited composition, property,
quantity, method, value, or range thereof in a manner that negates
an intended composition, property, quantity, method, value, or
range. Where modified by the term "substantially" the claims
appended hereto include equivalents according to this
definition.
Water-in-Oil Lattices
We have found inversion agents that provide rapid and complete
inversion of water-in-oil (w/o) lattices of water soluble polymers
under conditions wherein the water source used to invert the latex
is provided at high temperature, or includes a high level of total
dissolved solids, or is both high temperature and high total
dissolved solids. The w/o lattices useful in conjunction with the
compositions and methods of the invention are conventional lattices
employed in one or more EOR applications, wherein the inversion
agents are added to the w/o lattices to facilitate inversion to
yield a polymer solution for EOR. Polymer solutions for EOR
conventionally target a concentration of about 1.00 wt % or less.
The compositions and methods of the invention are easily carried
out using conventional materials and equipment familiar to one of
skill in w/o latex formation for EOR.
Polymers useful in the w/o lattices include conventional EOR
polymers as well as variations, mixtures, or derivatives thereof.
The invention is not particularly limited as to the polymer
employed in the water phase of the w/o lattices, however, in
embodiments the polymer is water soluble or fully dispersible to
result in increased viscosity suitable for one or more EOR
applications at concentrations of 1 wt % or less. Thus,
polyacrylamides, polyacrylates, copolymers thereof, and
hydrophobically modified derivatives of these (associative
thickeners) are the most commonly employed EOR polymers; all are
usefully employed in the w/o lattices. Associative thickeners
typically include about 1 wt % or less, based on total weight of
dry polymer, of a monomer having a long-chain hydrocarbon
functionality intended to produce physical or associative
crosslinking in a water-based polymer dispersion. Such
hydrophobically associating moieties are well known in the
industry. In some embodiments, the hydrocarbyl functionality
includes 8 to 20 carbons, or 10 to 20 carbons, or 12 to 20 carbons
arranged in a linear, branched, or cyclic conformation. In some
embodiments, the hydrophobically associating monomers are present
in the polymer compositions at about 1 wt % or less of the total
weight of the polymer composition, for example about 0.01 wt % to
1.00 wt %, or about 0.1 wt % to 1.00 wt %, or about 0.20 wt % to
1.00 wt % of the total weight of the polymer composition.
Other monomers usefully incorporated into the polymers and
copolymers with acrylamide, acrylic acid, or both include cationic
monomers, anionic monomers, and nonionic monomers. Nonlimiting
examples of cationic monomers include
N,N-diallyl-N,N-dimethylammonium chloride (DADMAC), N-alkyl
ammonium salts of 2-methyl-1-vinyl imidazole, N-alkyl ammonium
salts of 2-vinyl pyridine or 4-vinyl pyridine, N-vinyl pyridine,
and trialkylammonium alkyl esters and amides derived from acrylic
acid or acrylamide, respectively. Nonlimiting examples of anionic
monomers include methacrylic acid, 2-acrylamido-2-methylpropane
sulfonic acid (AMS), vinylphosphonic acid, and vinyl sulfonic acid
and conjugate bases or neutralized forms thereof (salts).
Nonlimiting examples of nonionic monomers include methacrylamide
and alkyl ester or amide derivatives of acrylic acid or acrylamide,
such as N-methyl acrylamide or butyl acrylate.
Polymers employed for EOR are desirably high molecular weight, as
conventionally employed in EOR applications. Higher molecular
weight increases the efficacy of the polymers in viscosifying
water. However, higher molecular weight also increases difficulty
in dissolution due to the high level of chain entanglement between
polymer strands as well as strong hydrogen bonding between polymer
functionalities such as amides and carboxylates. In embodiments,
the polymers usefully incorporated in the w/o lattices have a
weight average molecular weight (M.sub.w) of about 5.times.10.sup.5
to 1.times.10.sup.8 g/mol, or about 1.times.10.sup.6 to
5.times.10.sup.7 g/mol, or about 5.times.10.sup.6 to
2.times.10.sup.7 g/mol.
In embodiments, any polymer(s) useful in the w/o lattices disclosed
herein includes a cross-linking monomer or polymer. The crosslinker
may be labile, non-labile, or a combination thereof. The labile
crosslinker may be a glyoxal cross-linking monomer as described in
U.S. Patent Application Publication No. 2014/0209304, which is
incorporated by reference herein in its entirety. The non-labile
crosslinker may be methylene bis(acrylamide) as described in U.S.
Pat. No. 7,300,973, which is incorporated by reference herein in
its entirety. In embodiments, the polymer comprises about 1 mol %
to about 100 mol % acrylamide monomers, or about 1 mol % to about
90 mol %, or about 1 mol % to about 80 mol %, or about 1 mol % to
about 70 mol %, or about 1 mol % to about 60 mol %, or about 1 mol
% to about 50 mol %, or about 1 mol % to about 40 mol %, or about 1
mol % to about 30 mol %, or about 1 mol % to about 20 mol %, or
about 1 mol % to about 10 mol %, or about 10 mol % to about 100 mol
%, or about 20 mol % to about 100 mol %, or about 30 mol % to about
100 mol %, or about 40 mol % to about 100 mol %, or about 50 mol %
to about 100 mol %, or about 60 mol % to about 100 mol %, or about
70 mol % to about 100 mol %, or about 80 mol % to about 100 mol %,
or about 90 mol % to about 100 mol %, or about 20 mol % to about 80
mol, or about 30 mol % to about 70 mol %, or about 40 mol % to
about 60 mol %, or about 60 mol % to about 80 mol % acrylamide
monomers.
In embodiments, the polymer comprises about 0.1 ppm to about 20000
ppm labile or non-labile cross-linked monomer units based on the
weight of the polymer, or about 0.1 ppm to about 10000 ppm, or
about 0.1 ppm to about 5000 ppm, or about 0.1 ppm to about 1000
ppm, or about 0.1 ppm to about 100 ppm, or about 1 ppm to about
20000 ppm, or about 10 ppm to about 20000 ppm, or about 100 ppm to
about 20000 ppm, or about 1000 ppm to about 20000 ppm, or about
5000 ppm to about 20000 ppm, or about 10000 ppm to about 20000 ppm,
or about 100 ppm to about 10000 ppm, or about 1000 ppm to about
5000 ppm cross-linked monomer units based on the weight of the
polymer. In embodiments, the cross-linking monomer is glyoxal
bis(acrylamide).
In embodiments, the polymer including the cross-linking monomer
comprises about 100 ppm to about 10000 ppm of a w/o latex, or about
100 ppm to about 5000 ppm, or about 100 ppm to about 1000 ppm, or
about 100 ppm to about 500 ppm, or about 500 ppm to about 10000
ppm, or about 1000 ppm to about 10000 ppm, or about 5000 ppm to
about 10000 ppm, or about 500 ppm to about 5000 ppm, or about 100
ppm to about 1000 ppm, of a w/o latex.
In embodiments, one or more polymers are present substantially
within the water phase in an w/o latex. In embodiments, the
polymers are present within the w/o lattices at about 15 wt % to 70
wt % based on the total weight of the latex, or about 17 wt % to 70
wt %, or about 19 wt % to 70 wt %, or about 21 wt % to 70 wt %, or
about 23 wt % to 70 wt %, or about 25 wt % to 70 wt %, or about 15
wt % to 68 wt %, or about 15 wt % to 66 wt %, or about 15 wt % to
64 wt %, or about 15 wt % to 62 wt %, or about 15 wt % to 60 wt %,
or about 15 wt % to 58 wt %, or about 15 wt % to 56 wt %, or about
25 wt % to 65 wt %, or about 30 wt % to 60 wt %, or about 30 wt %
to 60 wt % based on the total weight of the latex.
The polymers present within the water phase of a w/o latex are
often, though not exclusively, formed in situ by dissolving one or
more monomers in the water phase, then adding a water phase into an
oil phase bearing a surfactant to form the emulsion, followed by
polymerization of the monomers to form a polymer w/o latex. Such
lattices are used for EOR applications.
Also present in the w/o latex is an amount of water sufficient to
form a water phase within the latex. Water is present in the w/o
latex at about 3 wt % to 50 wt % based on the total weight of the
latex, or about 5 wt % to 50 wt %, or about 10 wt % to 50 wt %, or
about 15 wt % to 50 wt %, or about 20 wt % to 50 wt %, or about 25
wt % to 50 wt %, or about 3 wt % to 45 wt %, or about 3 wt % to 40
wt %, or about 3 wt % to 35 wt %, or about 3 wt % to 30 wt %, or
about 3 wt % to 25 wt %, or about 5 wt % to 45 wt %, or about 5 wt
% to 40 wt %, or about 5 wt % to 35 wt %, or about 5 wt % to 30 wt
%, or about 5 wt % to 25 wt % based on the total weight of the w/o
latex. In some embodiments, the water is a water source.
Also present in the w/o latex is an amount of oil sufficient to
form an oil phase within the latex. In some embodiments, the oil is
not flammable at temperatures less than about 90.degree. C., or
less than about 80.degree. C., or less than about 70.degree. C. In
some embodiments, the oil is a mixture of compounds, wherein the
mixture is less than 0.1 wt % soluble in water at 25.degree. C. and
is substantially a liquid over the range of 20.degree. C. to
90.degree. C. In some embodiments, the oil comprises, consists
essentially of, or consists of one or more linear, branched, or
cyclic hydrocarbon moieties, aryl or alkaryl moieties, or
combinations of two or more such moieties. In some embodiments, the
oil has a density of about 0.8 g/L to 1.0 g/L, for example about
0.8 g/L to 0.9 g/L. Examples of suitable oils include decane,
dodecane, isotridecane, cyclohexane, toluene, xylene, and mixed
paraffin solvents such as those sold under the trade name
ISOPAR.RTM. by ExxonMobil Corp. of Irving, Tex. In embodiments, the
oil is present in the w/o latex at about 10 wt % to 40 wt % based
on the total weight of the w/o latex, or about 15 wt % to 40 wt %,
or about 20 wt % to 40 wt %, or about 22 wt % to 40 wt %, or about
24 wt % to 40 wt %, or about 26 wt % to 40 wt %, or about 28 wt %
to 40 wt %, or about 30 wt % to 40 wt %, or about 10 wt % to 38 wt
%, or about 10 wt % to 36 wt %, or about 10 wt % to 34 wt %, or
about 10 wt % to 32 wt %, or about 10 wt % to 30 wt %, or about 10
wt % to 25 wt %, or about 10 wt % to 20 wt %, or about 15 wt % to
35 wt %, or about 20 wt % to 30 wt % based on the total weight of
the w/o latex.
Also present in the w/o latex is one or more latex surfactants.
Latex surfactants are employed to form and stabilize the w/o
lattices during polymerization and to maintain latex stability
until inversion. Generally the latex surfactant is present at about
20 wt % or less based on the weight of the latex. Conventionally
employed surfactants for w/o lattices used for EOR applications
include nonionic ethoxylated fatty acid esters, ethoxylated
sorbitan fatty acid esters, sorbitan esters of fatty acids such as
sorbitan monolaurate, sorbitan monostearate, and sorbitan
monooleate, block copolymers of ethylene oxide and hydroxyacids
having a C.sub.10-C.sub.30 linear or branched hydrocarbon chain,
and blends of two or more of these targeted to achieve a selected
hydrophilic/lipophilic balance (HLB). Those of skill will
understand that a plethora of surfactants are employed throughout
the industry to form and stabilize w/o lattices, serving as
emulsifiers for polymerization of monomers and further maintaining
emulsion stability of the polymer formed therein until subsequent
use in the field. Any nonionic surfactants and blends thereof
conventionally employed in w/o lattices for EOR applications are
suitably employed in conjunction with the present invention. In
embodiments, the latex surfactant is a single nonionic surfactant
or blend thereof having a combined HLB value of about 2 to 10, for
example about 3 to 10, or about 4 to 10, or about 5 to 10, or about
6 to 10, or about 7 to 10, or about 8 to 10, or about 2 to 9, or
about 2 to 8, or about 2 to 7, or about 2 to 6, or about 2 to 5, or
about 3 to 9, or about 4 to 8.
Representative amounts of the above listed materials are suitably
included in one or more w/o lattices useful to stabilize one or
more EOR applications, wherein the amounts are suitably selected to
provide optimal kinetic stability of the emulsion. In some
embodiments, amounts of the above listed materials are suitably
employed in one or more w/o lattices to form a microemulsion or a
nanoemulsion, wherein such emulsions are characterized by one or
more properties of thermodynamic stability and optical
transparency. Representative amounts of these materials are shown
below, wherein these amounts are intended to be representative of
the w/o lattices useful in conjunction with the methods and
materials of the invention. Useful w/o lattices are not limited to
those shown below. A specific example of a w/o latex formulation is
provided in Example 3. Where amounts listed below do not add up to
100 wt %, one or more additional components are also present in the
latex.
TABLE-US-00001 Amount in a w/o Latex, wt % Phase Material Latex 1
Latex 2 Latex 3 Latex 4 Latex 5 Oil Oil 25 30 10 20 25 (solvent)
Latex 15 5 3 5 20 Surfactant Water Monomer 50 25 50 35 40 or
Polymer Water 5 40 10 3 10
The w/o lattices optionally include one or more additives. Salts,
buffers, acids, bases, dyes, thermal stabilizers, metal chelators,
coalescing solvents, and the like are optionally included in the
w/o lattices. In some embodiments, the additives include one or
more corrosion inhibitors, scale inhibitors, emulsifiers, water
clarifiers, hydrogen sulfide scavengers, gas hydrate inhibitors,
biocides, pH modifiers, antioxidants, asphaltene inhibitors, or
paraffin inhibitors. While the amount of an additive usefully
employed in the w/o latex depends on the additive and the intended
application, in general the amount of any individual additive is
about 0 wt % to 5 wt % based on the total weight of the w/o latex,
or about 0 wt % to 4 wt %, or about 0 wt % to 3 wt %, or about 0 wt
% to 2 wt %, or about 0 wt % to 1 wt % based on the total weight of
the latex.
In embodiments, the w/o lattices are made using conventional
equipment and methodology. Thus, in embodiments a w/o latex
containing the monomers is formed and the polymerization is
conducted within the water phase of the latex. In other embodiments
the polymer is formed in a water solution, and the solution is used
to form a w/o latex. In such embodiments, the w/o latex is formed
after polymerization is complete by adding one or more surfactants
and one or more oils to the water-based polymer composition and
emulsifying the combined components as described above.
In embodiments, the water in the w/o latex is substantially removed
after polymerization to produce a more concentrated latex product
by distillation, vacuum drying, spray drying, or a combination
thereof. In embodiments, the oil in the w/o latex is substantially
removed and recycled after polymerization to produce a more
concentrated latex product by distillation, vacuum drying, spray
drying, or any combination thereof.
Inversion Surfactants
Inversion of the presently disclosed w/o lattices is facilitated by
an inversion surfactant. Useful inversion surfactants comprise,
consist essentially of, or consist of surfactants or blends thereof
having an HLB of about 10 to 40, or about 10 to 35, or about 10 to
30, or about 10 to 25, or about 10 to 20, or about 10 to 15, or
about 15 to 40, or about 20 to 40, or about 25 to 40, or about 30
to 40, or about 35 to 40, or about 15 to 35, or about 20 to 30. In
some embodiments, the inversion surfactant is nonionic and includes
one or more compounds comprising one or more ethoxy groups, propoxy
groups, or a combination thereof. In some embodiments, the
inversion surfactant is ionic and includes one or more carboxylate,
sulfonate, phosphate, phosphonate, phosphonium, or ammonium
moieties. In some embodiments, the inversion surfactant includes a
linear or branched C.sub.8-C.sub.20 hydrocarbyl moiety. In some
such embodiments, the inversion surfactant is an alkoxylated
alcohol such as an ethoxylated, propoxylated, or
ethoxylated/propoxylated alcohol, wherein the alcohol includes a
linear or branched C.sub.8-C.sub.20 hydrocarbyl moiety. In some
such embodiments, the inversion surfactant includes about 4 and 40
ethylene oxide repeat units and 0 to about 10 propylene oxide
repeat units. In some embodiments, the inversion surfactant
includes a sorbitan moiety. In some embodiments, the inversion
surfactant is a block copolymer. In some such embodiments, the
block copolymer is linear, branched, or hyperbranched. Examples of
suitable inversion surfactants are listed in McCutcheon's
Emulsifiers & Detergents, MC Publishing Co., 2015 edition.
The inversion surfactant may be added before, concurrently with, or
after addition of an inversion agent, described below, to a w/o
latex. In embodiments, in order to facilitate inversion of a w/o
latex, the inversion surfactant is added to a latex at about 0.1 wt
% to 20 wt % based on the total weight of the w/o latex, or about
0.1 wt % to 15 wt %, 0.1 wt % to 10 wt %, or about 0.1 wt % to 7.5
wt %, 0.1 wt % to 6.0 wt % based on the total weight of the w/o
latex, or about 0.5 wt % to 5.5 wt %, or about 1.0 wt % to 5.0 wt
%, or about 1.5 wt % to 4.5 wt %, or about 2.0 wt % to 4.0 wt %, or
about 2.5 wt % to 3.5 wt %, or about 0.1 wt % to 5.5 wt %, or about
0.1 wt % to 5.0 wt %, or about 0.1 wt % to 4.5 wt %, or about 0.1
wt % to 4.0 wt %, or about 0.1 wt % to 3.5 wt %, or about 0.5 wt %
to 6.0 wt %, or about 1.0 wt % to 6.0 wt %, or about 1.5 wt % to
6.0 wt %, or about 2.0 wt % to 6.0 wt %, or about 2.5 wt % to 6.0
wt %, or about 3.0 wt % to 6.0 wt %, based on the total weight of
the w/o latex.
The amount of inversion surfactant may be reduced when an inversion
agent (described below) is added to a w/o latex. In embodiments, an
inversion agent is added to a w/o latex and the amount of inversion
surfactant is reduced by up to 50% compared to a w/o latex that
does not include an inversion agent. In embodiments, the inversion
agent is added to a latex at about 0.1 wt % to 10 wt % based on the
total weight of the w/o latex, or about 0.1 wt % to 7.5 wt %, 0.1
wt % to 5.0 wt % based on the total weight of the w/o latex, or
about 1.5 wt % to 4.5 wt %, or about 2.0 wt % to 4.0 wt %, or about
2.5 wt % to 3.5 wt %, or about 0.1 wt % to 4.5 wt %, or about 0.1
wt % to 4.0 wt %, or about 0.1 wt % to 3.5 wt %, or about 0.5 wt %
to 5.0 wt %, or about 1.0 wt % to 5.0 wt %, or about 1.5 wt % to
5.0 wt %, or about 2.0 wt % to 5.0 wt %, or about 2.5 wt % to 5.0
wt %, or about 3.0 wt % to 5.0 wt %, based on the total weight of
the w/o latex.
Inversion Agents
We have found inversion agents that when added to conventional w/o
lattices of water soluble polymers in the presence of an inverting
surfactant form invertible lattices. The invertible lattices are
characterized by the rapid and complete inversion thereof under
conditions wherein the water source used to invert the latex is
about 30.degree. C. to 100.degree. C., or about 40.degree. C. to
100.degree. C., or about 50.degree. C. to 100.degree. C., or about
60.degree. C. to 100.degree. C. Further, the invertible lattices
are characterized by the rapid and complete inversion thereof under
conditions wherein the water source used to invert the latex
includes about 0.1 to 30 wt % total dissolved solids. Still
further, the invertible lattices are characterized by the rapid and
complete inversion thereof under conditions wherein the water
source used to invert the latex is about 30.degree. C. to
100.degree. C. and further includes about 0.1 to 30 wt % total
dissolved solids.
In embodiments, inversion agents of the invention comprise, consist
essentially of, or consist of a phosphorus functional compound. As
used herein, a phosphorus functional compound is a water-soluble
compound having at least one phosphono (RP(.dbd.O)(OH).sub.2)
moiety, which as used herein is a phosphonic acid moiety
(--P(.dbd.O)(OH).sub.2) or a conjugate base thereof further
comprising a cationic moiety such as a metal cation, organic
cation, or combinations thereof, or at least one phosphino moiety,
which as used herein is a R.sub.2P(.dbd.O)(OH) or
R.sub.2P(.dbd.O)(OR) moiety or a conjugate base of any of the
foregoing further comprising a cationic moiety such as a metal
cation, organic cation, or combinations thereof; and at least one
carboxylate (--COOH) moiety, which as used herein is a carboxylic
acid moiety or a conjugate base thereof further comprising a
cationic moiety such as a metal cation, organic cation, or
combinations thereof. As used herein, a water-soluble compound is
at least 5 wt % soluble in water at 20.degree. C., or at least 7 wt
% soluble in water at 20.degree. C., or at least 10 wt % soluble in
water at 20.degree. C. In some embodiments, the phosphorus
functional compound is oligomeric or polymeric; that is, it
includes identifiable repeat units attributable to condensation or
addition type reactions. In some embodiments, the phosphorus
functional compound is not oligomeric or polymeric; that is, it
does not include identifiable repeat units attributable to
condensation or addition type reactions. In some embodiments, the
phosphorus functional compound is characterized by the absence of
phosphate moieties. In some embodiments, the phosphorus functional
compound has 1 to 5 phosphono or phosphino moieties, or any
combination thereof. In some embodiments, the phosphorus functional
compound has 1 to 5 phosphono moieties, or 1 to 4, or 1 to 3, or 1
to 2 phosphono moieties. In some embodiments, the phosphorus
functional compound has 1 to 5 phosphino moieties, or 1 to 4, or 1
to 3, or 1 to 2 phosphino moieties. As used herein, the term
"carboxylate" (or "acid") means a carboxylic acid moiety or a
conjugate base thereof or an ester thereof with an alkanol having 1
to 4 carbons, unless otherwise specified. In some embodiments, the
phosphorus compound has 1 to 5 carboxylate moieties, or 1 to 4, or
1 to 3, or 1 to 2 carboxylate moieties. In some embodiments, the
phosphorus functional compound includes one or more amino moieties.
In some embodiments, the phosphorus functional compound includes
one or more hydroxyl moieties.
In embodiments, the phosphorus functional compounds are not surface
active agents in w/o lattices. That is, they do not tend to lower
the surface tension between water and oil phases in a w/o latex. As
used herein, a compound that is not a surfactant is one that
reduces the surface tension of water in a 0.5% active solution at
room temperature by 25% or less, by 20% or less, or by 10% or less,
or by 5% or less. (Example 4.)
In embodiments, inversion agents of the invention comprise, consist
essentially of, or consist of a hydrotrope. As used herein, a
hydrotrope is a water soluble compound that solubilizes hydrophobic
compounds in an aqueous solution and that includes at least one
hydrophilic and at least one minor hydrophobic moiety. As used
herein, a minor hydrophobic moiety is one that is insufficient to
promote spontaneous self-aggregation or is insufficient to promote
accumulation at interfaces or is not a long uninterrupted
hydrophobic chain or is any combination of the foregoing. As used
herein, a long uninterrupted hydrophobic chain is a hydrocarbyl
moiety having 5 or more carbon atoms.
In embodiments, inversion agents of the invention comprise, consist
essentially of, or consist of compounds with an HLB as calculated
by the Davies formula: HLB=/.SIGMA.(Hydrophilic group
contributions)-.SIGMA.(Hydrophobic group contributions)+7 of
greater than about 45, or greater than about 50, or greater than
about 55, or greater than about 60, or greater than about 65, or
greater than about 70, or about 45 to 150, or about 45 to 140, or
about 45 to 130, or about 45 to 120, or about 45 to 110, or about
45 to 100, or about 45 to 90, or about 50 to 150, or about 55 to
150, or about 60 to 150, or about 65 to 150, or about 70 to 150. As
calculated herein, sulfonate values were used as a proxy for
phosphonate values.
Examples of useful phosphorus functional compounds include
2-phosphonatobutane-1,2,4-tricarboxylic acid, 2-phosphonoacetic
acid, 2-hydroxy-2-phosphono acetic acid,
N,N-bis(phosphonomethyl)glycine, N-(phosphonomethyl)glycine,
2-phosphonopropanoic acid, 3-phosphonopropanoic acid,
4-phosphonobutanoic acid, 2-amino-5-phosphonopentanoic acid,
2-(phosphonomethyl)pentanedioic acid, 2-amino-3-phosphonopropionic
acid, 2-amino-4-methyl-5-phosphono-3 pentenoic acid,
(2R)-2-amino-3-phosphonopropanoic acid, phosphonoformic acid,
bis(1-carboxy-1-hydroxy)phosphinic acid, and phosphinosuccinic
oligomer (PSO), and the like and salts thereof. PSO has the
following probable formula:
##STR00001## wherein M is H, Na, K, NH.sub.4 or mixtures thereof,
and m and n are either 0 or a small whole number with the proviso
that either m or n is a small whole number and the sum of m plus n
is greater than 2. The oligomer is as described in U.S. Pat. Nos.
5,018,577, 5,023,000, 5,085,794, and 6,572,789, which are
incorporated by reference herein each in its entirety.
Unexpectedly, the inversion agent, or the inversion agent in
combination with the inversion surfactant, reduces the bulk
viscosity of the invertible latex. In embodiments, reduced bulk
viscosity provides better pumpability for pumping and transferring
the invertible latex and/or the polymer flooding solution. The
inversion agent, or the inversion agent in combination with the
inversion surfactant, may increase the speed of the inversion
process, increase the completeness of the inversion process, or
both increase the speed and completeness. The resulting polymer
flooding solution may thereby demonstrate improved performance.
In embodiments, the inversion agents, or the inversion agents in
combination with an inversion surfactant, of the present disclosure
facilitate inversion of an invertible latex compared to an
invertible latex comprising no inversion agent and/or compared to
an invertible latex comprising a known inversion agent such as
glycerol. The inversion agents, or the inversion agents in
combination with an inversion surfactant, of the present disclosure
increase the speed and/or completeness of the inversion process
compared to an invertible latex comprising no inversion agent
and/or compared to an invertible latex comprising a known inversion
agent such as glycerol.
In embodiments, the inversion agents, or the inversion agents in
combination with an inversion surfactant, facilitate inversion of
an invertible latex under conditions wherein the water source used
to invert the latex is about 0.degree. C. to 100.degree. C. In some
examples, the inversion agents, or the inversion agents in
combination with an inversion surfactant, facilitate inversion of
an invertible latex under conditions wherein the water source used
to invert the latex is about 60.degree. C. (Example 3.)
In embodiments, the inversion agents, or the inversion agents in
combination with an inversion surfactant, facilitate inversion of
an invertible latex under conditions wherein the water source used
to invert the latex includes about 0.1 to 30 wt % total dissolved
solids. In some examples, the inversion agents, or the inversion
agents in combination with an inversion surfactant, facilitate
inversion of an invertible latex under conditions wherein the water
source used to invert the latex includes about 3.5% total dissolved
solids. (Example 3.)
In embodiments, the inversion agents, or the inversion agents in
combination with an inversion surfactant, facilitate inversion of
an invertible latex under conditions wherein the water source used
to invert the latex is about 0.degree. C. to 100.degree. C. and
includes about 0.1 to 30 wt % total dissolved solids. In some
examples, the inversion agents, or the inversion agents in
combination with an inversion surfactant, facilitate inversion of
an invertible latex under conditions wherein the water source used
to invert the latex is about 60.degree. C. and includes about 3.5%
total dissolved solids. (Example 3.)
Without being limited to any mechanism or mode of action, inversion
agents may form hydrogen bonds and/or may affect the osmotic
pressure of monomer- or polymer-comprising droplets of the
discontinuous internal water phase within the continuous oil phase
of a w/o latex. The inversion agents may increase the osmotic
pressure of the droplets such that the droplets swell. When
combined with a water source to form a polymer flooding solution,
the swollen droplets may rupture more easily, facilitating the
release of the monomer or polymer into the water. Separately from,
or in addition to, the effect on osmotic pressure, the inversion
agents may chelate ions within the droplets. Chelation may prevent
or limit interaction of ions with the surfactant and thereby
facilitate inversion. In embodiments, the branched structure of
some inversion agents may facilitate inversion compared to the
inclusion of straight chain molecules.
In embodiments, the inversion agent is added to a latex in an
amount sufficient to facilitate the inversion of a w/o latex. The
amount is not so high that it causes the emulsion to break or
otherwise be unstable. In embodiments, the inversion agent is added
to a latex in an amount less than amounts of known inversion
agents. For example, the presently disclosed inversion agent may be
added in an amount of from about 0.1 wt % to 5.0 wt % based on the
total weight of the w/o latex. In contrast, and as disclosed in US
2014/0051620, glycerol is preferably added in an amount of from
about 5 to about 20% by weight.
In embodiments, in order to facilitate inversion of a w/o latex,
the inversion agent is added to a latex at about 0.1 wt % to 20.0
wt % based on the total weight of the w/o latex, or about 0.1 wt %
to 15.0 wt %, or about 0.1 wt % to 10.0 wt %, or about 0.1 wt % to
7.5 wt %, or about 0.1 wt % to 5.0 wt %, or about 0.5 wt % to 4.5
wt %, or about 1.0 wt % to 4.0 wt %, or about 1.5 wt % to 3.5 wt %,
or about 2.0 wt % to 3.0 wt %, or about 0.1 wt % to 4.5 wt %, or
about 0.1 wt % to 4.0 wt %, or about 0.1 wt % to 3.5 wt %, or about
0.1 wt % to 3.0 wt %, or about 0.5 wt % to 5.0 wt %, or about 1.0
wt % to 5.0 wt %, or about 1.5 wt % to 5.0 wt %, or about 2.0 wt %
to 5.0 wt %, based on the total weight of the w/o latex.
The inversion agent is added to a latex at an inversion
surfactant:inversion agent wt:wt ratio of about 10:1, or about
7.5:1, or about 5:1, or about 2.5:1, or about 2:1, or about 1.75:1,
or about 1.5:1, or about 1.25:1, or about 1:1, or about 1:10, or
about 1:7.5, or about 1:5, or about 1:2.5, or about 1:2, or about
1:1.75, or about 1:1.5, or about 1:1.25.
The inversion surfactant and inversion agent are added to a latex
in a combined amount ([inversion surfactant+inversion agent]) of
about 0.1 wt % to 20.0 wt % based on the total weight of the w/o
latex, or about 0.5 wt % to 18.0 wt %, or about 1.0 wt % to 16.0 wt
%, or about 1.5 wt % to 14.0 wt %, or about 2.0 wt % to 12.0 wt %,
or about 2.5 wt % to 10.0 wt %, or about 3.0 wt % to 8.0 wt %, or
about 3.5 wt % to 7.5 wt %, or about 4.0 wt % to 7.0 wt %, or about
4.5 wt % to 6.5 wt %, or about 0.1 wt % to 18.0 wt %, or about 0.1
wt % to 16.0 wt %, or about 0.1 wt % to 14.0 wt %, or about 0.1 wt
% to 12.0 wt %, or about 0.1 wt % to 10.0 wt %, or about 0.1 wt %
to 8.0 wt %, or about 0.1 wt % to 7.5 wt %, or about 0.1 wt % to
7.0 wt %, or about 0.1 wt % to 6.5 wt %, or about 0.5 wt % to 20.0
wt %, or about 1.0 wt % to 20.0 wt %, or about 1.5 wt % to 20.0 wt
%, or about 2.0 wt % to 20.0 wt %, or about 2.5 wt % to 20.0 wt %,
or about 3.0 wt % to 20.0 wt %, or about 3.5 wt % to 20.0 wt %, or
about 4.0 wt % to 20.0 wt %, or about 4.5 wt % to 20.0 wt %, or
about 5.0 wt % to 20.0 wt %, or about 5.5 wt % to 20.0 wt %, or
about 6.0 wt % to 20.0 wt %, or about 6.5 wt % to 20.0 wt %, or
about 7.0 wt % to 20.0 wt %, or about 7.5 wt % to 20.0 wt %, or
about 8.0 wt % to 20.0 wt %, based on the total weight of the w/o
latex.
Invertible Lattices
Addition of an inversion agent of the present disclosure to a
conventional w/o latex in the presence of an inverting surfactant,
results in an invertible latex of the invention. The inversion
agents may be added to the w/o latex before or after
polymerization. The inversion agents may be added to a w/o latex
before or after addition of an inverting surfactant. In some
embodiments, the inversion agents are characterized as not being
surfactants, that is, they are not surface active. Thus, in some
embodiments, the invertible lattices of the invention comprise,
consist essentially of, or consist of a conventional w/o latex as
described above, an inversion surfactant, and an inversion agent.
In embodiments, the inversion agent is added to the w/o latex
before polymerizing the monomer via a conventional free-radical or
redox initiation. In other embodiments, the inversion agent is
added directly to the w/o latex after polymerization is
complete.
The invertible lattices of the invention are stable or even shelf
stable. That is, the invertible lattices do not exhibit any
observed signs of gross phase separation, coagulation, or
precipitation for at least 24 hours at ambient laboratory
temperatures. In embodiments, the invertible latex is stable under
common ambient conditions for at least 1 day at 20.degree.
C.-25.degree. C., or for at least 2 days at 20.degree.
C.-25.degree. C., or for at least 1 week at 20.degree.
C.-25.degree. C., or for at least 2 weeks at 20.degree.
C.-25.degree. C., or for at least 1 month at 20.degree.
C.-25.degree. C., or for at least 2 months at 20.degree.
C.-25.degree. C., or for at least 1 day at 50.degree. C., or for at
least 2 days at 50.degree. C., or for at least 5 days at 50.degree.
C., or for at least 10 days at 50.degree. C., or for at least 30
days at 50.degree. C.
Inversion of the Invertible Lattices
The invertible lattices of the invention invert rapidly and
completely when contacted with a water source having high
temperature, high total dissolved solids, or both to yield a
polymer flooding solution. Numerous advantages are realized by use
of the invertible lattices of the invention; principal of these is
the time savings realized when rapid and complete inversion
replaces multi-step, slow, or incomplete inversion in the field.
Both the invertible lattices and the resulting polymer flooding
solutions are characterized by the absence of the manifestations of
latex or inversion instability; avoiding latex or inversion
instability prevents downtime in the field necessitated by plugged
or fouled equipment and avoids damages to reservoirs and plugging
the formation.
During inversion, a water source is contacted with an invertible
latex in one or more steps including one or more mixing and/or
shearing processes to result in a polymer flooding solution having
1 wt % polymer or less. In some embodiments, the invertible
lattices of the invention provide for a simple, one-step inversion
process characterized by absence of instabilities manifested as
coagulation or precipitation of polymer or gross phase separation
of the water phase from the oil phase prior to dissolution. It is a
feature of the invention that the invertible lattices of the
invention provide for a simple, one-step inversion process in the
presence of water sources contacted with the invertible latex at
temperatures of about 30.degree. C. to 100.degree. C., or about
40.degree. C. to 100.degree. C., or about 50.degree. C. to
100.degree. C., or about 60.degree. C. to 100.degree. C. It is a
feature of the invention that the invertible lattices of the
invention provide for a simple, one-step inversion process in the
presence of water sources contacted with the invertible latex
wherein the water source contacting the invertible latex includes
about 0.1 to 30 wt % total dissolved solids. It is a feature of the
invention that the invertible lattices of the invention provide for
a simple, one-step inversion process wherein the water source
contacting the invertible latex includes about 0.1 to 30 wt % total
dissolved solids and further contacts the inversion composition at
about 30.degree. C. to 100.degree. C.
During the inversion process, the presence of the inversion agent
reduces or prevents the coagulation of the polymer in the polymer
flooding solution; reduces or prevents "hardening" or "raincycle"
(evaporation, condensation) during storage that leads to formation
of viscous masses on the surface and in the bulk; and prevents
formation of lumps, skin, crust, or "waxing" due to the sensitivity
of the invertible latex to shear during the pumping, filtration and
stirring steps to which the lattices are subjected in EOR
applications, which in turn leads to the breakage of the mechanical
seals of the pumps or the plugging of the filters, valves and check
valves.
The polymer flooding solution typically includes about 1 wt % or
less of polymer, other (residual) compounds from the inverted
latex, and any dissolved solids present in the water source. The
polymer flooding solutions of the invention are characterized by
absence of gel particles, absence of gross phase separation, and/or
absence other manifestations of inversion instability of w/o
lattices.
Inversion of the invertible lattices to form the polymer flooding
solutions is accomplished using conventional techniques and
equipment, which is an unexpected benefit of employing the
inversion agent of the invention using water sources that are high
temperature, high total dissolved solids, or both high
temperature/high total dissolved solids water sources. In some
embodiments, inversion of invertible lattices to form the polymer
flooding solutions is suitably accomplished in a single step
including dilution and mixing of the invertible latex with the
water source to the target polymer concentration in the polymer
flooding solution. In other embodiments, inversion of invertible
lattices to form the polymer flooding solutions is suitably
accomplished in two dilution/mixing steps to reach the target
polymer concentration. In some embodiments, the inversion and
dilution to a target concentration of less than 1 wt % is
accomplished in about 1 to 15 minutes, for example about 1 to 14, 1
to 13, 1 to 12, 1 to 11, 1 to 10, 1 to 9, 1 to 8, 1 to 7, 1 to 6, 1
to 5, 2 to 15, 3 to 15, 4 to 15, 5 to 15, 6 to 15, 7 to 15, 8 to
15, 9 to 15, 10 to 15, 2 to 10, 2 to 9, 2 to 8, 3 to 10, 3 to 9, 3
to 8, 4 to 10, 4 to 9, 4 to 8, or 4 to 7 minutes.
After inversion, the polymer flooding solutions comprise about 100
ppm to 10,000 ppm (0.01 wt % to 1.00 wt %) polymer, or about 200
ppm to 5000 ppm, or about 200 ppm to 4000 ppm, or about 200 ppm to
3000 ppm, or about 200 ppm to 2500 ppm polymer. In some embodiments
the water source contacts the invertible latex at a temperature of
about 30.degree. C. to 100.degree. C., or about 40.degree. C. to
100.degree. C., or about 50.degree. C. to 100.degree. C., or about
60.degree. C. to 100.degree. C. In other embodiments, the water
source includes about 0.1 to 30 wt % total dissolved solids. In
still other embodiments, the water source includes about 0.1 to 30
wt % total dissolved solids and further contacts the inversion
composition at about 30.degree. C. to 100.degree. C.
A water source is water or a water solution having up to about 30.0
wt % total dissolved solids (TDS), or about 0.1 wt % to 29.0 wt %,
or about 0.5 wt % to 28.0 wt %, or about 1.0 wt % to 27.0 wt %, or
about 2.0 wt % to 25.0 wt %, or about 3.0 wt % to 20.0 wt % TDS.
"High TDS" water sources have TDS of at least about 1 wt %. Thus in
embodiments a water source includes one or more dissolved solid
materials including but not limited to salts, ions, buffers, acids,
bases, surfactants, compounds employed in the water used in mining
operations, or other dissolved, dispersed, or emulsified compounds,
materials, components, or combinations thereof. Nonlimiting
examples of water sources include hard water, produced water from
mining operations, brackish water, sea water, municipal waste
water, tap water, "gray water", and the like. Water sources having
high TDS and high temperature are often encountered in use for EOR
applications. For example, hydraulic fracturing and conventional
oil recovery often results in produced water having high TDS,
temperatures in excess of 60.degree. C., or both; rather than use
fresh water, in such situations it is economical to reuse the
produced water as the water source for inversion processes.
In some embodiments, the method of inverting the invertible
lattices involves conventional inverting equipment. While inverting
a latex is often accomplished in the field using high shear,
stepwise dilution for efficiency in achieving full dilution and
hydration of a polymer at the desired use level, we have found that
relatively low shear mixing is advantageous in some embodiments for
inverting the invertible lattices of the invention. Such techniques
are advantageous because avoiding some or all shear on the polymer
chains during dissolution results in a higher final viscosity of
the polymer flooding solution by reducing or eliminating chain
scission of the high molecular weight polymers. It is a feature of
the invertible lattices of the invention that low-shear techniques
that avoid substantial amounts of chain scission are suitably used
in rapid inversion to result in polymer flooding solutions
characterized by lack of manifestations of instability as discussed
above.
Low shear inverting equipment employed to invert the invertible
lattices of the invention include static mixers. For example, U.S.
Pat. No. 8,383,560 describes an apparatus employing a two-step
inversion apparatus. In the first step, a w/o polymer latex is
diluted to yield a polymer solution having about 5000 ppm to 20,000
ppm polymer solids employing a first static mixer having a pressure
drop of at least 2 bars between the inlet and outlet thereof. In
the second step, the partially diluted latex is applied to a second
static mixer having a pressure drop of at least 1 bar between the
inlet and outlet, and is further diluted to result in a polymer
solution having between 500 and 3000 ppm, in practice between 1000
and 2000 ppm polymer solids. Such a two-step dilution system is
usefully employed in conjunction with the invertible lattices of
the present invention. Conventional static mixers, as described in
U.S. Pat. No. 8,383,560 are usefully employed; other low shear
mixers and pumps are used in addition to, or as a replacement for,
one or more static mixers described in U.S. Pat. No. 8,383,560.
Unexpectedly, we have further found that it is possible to employ a
single stage inversion of the invertible lattices by employing the
inversion agents of the invention: that is, a single dilution step
with a water source is usefully employed to dilute the invertible
lattices to form a polymer flooding solution at the final use
concentration of about 100 ppm to 10,000 ppm. No intermediate or
step-down dilution is required to form the polymer flooding
solution. The polymer flooding solutions of the invention are
characterized by the substantial absence of gels and solution
instabilities in the field. This finding is significant because
conventional w/o lattices, subjected to a single dilution step in
the field, result in substantial gel particles and/or solution
instabilities that cause plating out or plugging of equipment used
to carry out EOR by polymer flooding. Conventional water-in-oil EOR
lattices require two or more dilution steps and several hours to
complete inversion to result in a polymer solution.
In some embodiments, after the invertible lattices are contacted
with water source to form a polymer flooding solution in a single
dilution step, the polymer continues to build viscosity for about
0.5 minute to 120 minutes, or about 0.75 minute to 115 minutes, or
about 1 minute to 110 minutes, or about 2 minutes to 105 minutes,
or about 5 minutes to 100 minutes, or about 10 minutes to 90
minutes, or about 15 minutes to 80 minutes, or about 5 minutes to
70 minutes, or about 10 minutes to 70 minutes, or about 20 minutes
to 70 minutes, or about 30 minutes to 70 minutes, or about 40
minutes to 70 minutes, or about 50 minutes to 70 minutes, or about
5 minutes to 60 minutes, or about 10 minutes to 60 minutes, or
about 20 minutes to 60 minutes, or about 30 minutes to 60 minutes,
or about 40 minutes to 60 minutes.
The inverted w/o lattices, that is, the polymer flooding solutions
of the invention, are characterized by a substantial freedom from
gel particles and subsequent final polymer solution instability.
The test for gel particle formation consists of measuring the time
taken to filter given masses of solution containing 1000 ppm (0.1
wt %) polymer. The solution is contained in a steel bell filter
ratio housing pressurized to and maintained at 20 psi. The filter
has a diameter of 90 mm and a pore size of 5 microns.
The times required to obtain 90 g (t90 g); 120 g (t120 g); 180 g
(t180 g and 210 g (t210 g) of filtrate are therefore measured and a
filtration quotient (or filter ratio denoted "FR") is defined,
expressed as:
.times..times..times..times..times..times..times..times..times..times..ti-
mes..times..times..times. ##EQU00001##
The time measurement accuracy is 0.1 second.
The FR thus represents the capacity of the polymer solution to plug
the filter for two equivalent consecutive mass samples. A typical
acceptability criterion of the industry is FR<1.5. Conventional
w/o lattices employed for formation of polymer flooding solutions
cannot achieve this level of filterability even after several hours
of stirring in the laboratory. However, the invertible lattices of
the invention are characterized in that FR<1.5 is suitably
achieved in about 5 minutes or less when a water source is
contacted with a invertible latex of the invention, for example
about 1 to 5 minutes, or about 2 to 5 minutes, or about 3 to 5
minutes, or about 4 to 5 minutes, or about 1 to 4 minutes, or about
1 to 3 minutes.
In a nonlimiting example of an EOR application, a w/o latex is
applied to a reservoir as follows. An invertible latex is
introduced to a mixing apparatus, wherein a water source is
contemporaneously introduced into the apparatus in an amount
suitable to form a polymer solution of the desired concentration. A
water source, such as a high temperature water source, a high total
dissolved solids water source, or a high temperature/high total
dissolved solids water source is added to the invertible latex in
an amount suitable to target the selected final polymer
concentration. The water source is added prior to or
contemporaneously with the carrying out of one or more mixing
processes to thoroughly mix the invertible latex with the water
source and accomplish the inversion.
In some embodiments, inversion of the invertible lattices is
suitably carried out using conventional equipment and methods used
to invert lattices in the field. Employing conventional equipment
and methods familiar to those of skill in inverting w/o lattices
for EOR applications, it is possible to invert the invertible latex
in less than 5 minutes, for example about 1 second to 5 minutes, or
about 20 seconds to 5 minutes, or about 30 seconds to 5 minutes, or
about 1 minute to 5 minutes, or about 2 minutes to 5 minutes, or
about 1 second to 4 minutes, or about 1 second to 3 minutes, or
about 1 second to 2 minutes, or about 1 second to 1 minute.
In some embodiments, inversion is suitably carried out by
subjecting the invertible lattices of the invention to a
single-step inversion by diluting the lattices with a water source
and efficiently mixing the water source and the invertible latex in
a single step. Devices suitable to achieve a one-step inversion
include static mixers, paddle or blade mixers, mixing pumps, and
the like. Any devices conventionally employed for w/o latex
inversion are suitably employed to invert the invertible lattices
of the invention.
While the foregoing description is centered on EOR applications,
water soluble polymers and lattices thereof are also usefully
employed in one or more papermaking applications using a
Fourdrinier or inclined Fourdrinier apparatus, wherein water-based
furnishes dispensed onto a wire can include an EOR-type polymer to
improve the rheological profile of the furnish as dictated by
machine or application parameters. In such applications, the
invertible lattices of the invention are advantageously employed
due to rapid inversion upon addition to a furnish (a water-based
dispersion of fibers) to result in a polymer solution similar to
the polymer flooding solutions as described above. In papermaking
applications, it is desirable to use tap water or another
water-based solution to form the furnish and the w/o lattices of
the invention are suitable for use with water-based furnishes
employing water-based solutions having high TDS, at elevated
temperatures, or both. Papermaking includes making paper--that is,
cellulose based mats--as well as other nonwoven fibrous mats such
as filtration media that employ e.g. thermoplastic and glass fibers
in addition to or instead of cellulose based fibers. One of skill
will appreciate that other industrial uses, such as in wastewater
treatment, mining services, or energy services, of the w/o lattices
of the invention are similarly envisioned.
EXAMPLES
Abbreviations
BPMG--Bis(phosphonomethyl)glycine
HPA--2-Hydroxy-2-phosphonoacetic acid
PBTC--2-Phosphonobutane-1,2,4-tricarboxylic acid
PP--Propyl phosphonic acid
PSO--Phosphinosuccinic oligomer
Example 1
Water-in-oil lattices were prepared using the components of Table
1.
TABLE-US-00002 TABLE 1 Components of w/o latices. Material Wt %
Water Phase Acrylamide 49.5% 38.2953 DI water 15.0941 Acrylic acid
7.6437 Sodium hydroxide 8.2524 Sodium formate 0.0340 VERSENEX .RTM.
80 (pentasodium 0.0300 diethylenetriaminepentaacetate) Oil Phase
Hydrocarbon solvent (hydrotreated light distillate) 27.1845
Sorbitan sesquioleate (Span 83 .TM. or Arlacel 83 .TM., Croda
0.8234 International PLC, Yorkshire, United Kingdom)
Polyoxyethylene (40-50) sorbitol hexaoleate 2.5747 HYPERMER .RTM.
B210 (Croda International PLC, Yorkshire, 0.0194 United Kingdom)
Initiator 2,2'-azobisisobutyronitrile 0.0288 Post
treatment/reduction of acrylamide residual TBHP (tertiary butyl
hydroperoxide) 70% 0.0064 Sodium metabisulfite 0.0133
Polymerization of the components of Table 1 was conducted at 38 to
44.degree. C. for 3 to 4 hours and post heated for 57.degree. C.
for 30 minutes. The latex polymer (an acrylic acid and acrylamide
copolymer) was then agitated at 800 rpm using a cage stirrer at
room temperature. A phosphorus functional inversion agent (2-3 wt
%, neutralized to pH 7), then a stabilizer (ammonium thiocyanate,
0.125%), and then an inverting surfactant (tridecyl alcohol
ethoxylate (TDA-12), 3.3%) were added with agitation. Control
lattices did not include an inversion agent. The resulting blend
was stirred at room temperature for 30 minutes to produce a w/o
latex for the invertibility analysis of Example 3.
Example 2
The bulk viscosity (BV) of each of the w/o lattices produced in
Example 1 was measured at room temperature using a Brookfield DV-E
viscometer. BV data for w/o lattices comprising 3 wt % of a
phosphorus functional inversion agent are presented in Table 2.
TABLE-US-00003 TABLE 2 Bulk viscosity data of w/o latices of
Example 1 comprising 3 wt % of a phosphorus functional inversion
agent. Inversion Agent (3 wt %) BV (cps) None (Control) 1990
Glycerol 1832 Bis(phosphonomethyl)glycine 1980
2-Hydroxy-2-phosphonoacetic acid 1300
2-Phosphonobutane-1,2,4-tricarboxylic acid 624 Phosphinosuccinic
oligomer 1980
The data of Table 2 demonstrate that the w/o lattices of Example 1
comprising 3 wt % of a phosphorus functional inversion agent had
bulk viscosities lower than w/o lattices comprising no inversion
agent (control w/o lattices) and some of the w/o lattices of
Example 1 had bulk viscosities lower than w/o lattices comprising 3
wt % glycerol. The inclusion of HPA or PBTC in w/o lattices
decreased bulk viscosity 35% to 69% over control lattices and 29%
to 66% over w/o lattices comprising glycerol. The lower BVs of the
w/o lattices comprising a phosphorus functional inversion agent
provide better pumpability for pumping and transferring the
invertible lattices.
Example 3
The invertibility of the w/o lattices of Example 1 was determined
by torque monitor technique. A torque monitor is a qualitative
analytical tool comprising a DC stir motor, a controller that can
report the torque (DC voltage) required to maintain a constant stir
speed, and a computer to record the torque reading as a function of
time. In a typical experiment, the w/o latex was added to a
stirring solution of 3.5% synthetic sea water (Glas-Col Precision
Stirrer, obtained from Glas-Col LLC of Terre Haute, Ind.), and the
generated torque was monitored as a function of time
([polymer]=10000 ppm, 400 rpm). The analysis was run for 20-30 min
to confirm the torque remained stable. Experiments were conducted
at 60.degree. C. with high salinity conditions to evaluate the
performance of w/o lattices under high stress conditions.
The 3.5% synthetic seawater used in the present Example was formed
by blending the components of Table 3.
TABLE-US-00004 TABLE 3 Components of 3.5% synthetic seawater.
Reagent Amount (g) Deionized water 957.99 Sodium bicarbonate
(NaHCO.sub.3) 0.01 Calcium chloride CaCl.sub.2.cndot.2H.sub.2O 1.57
Sodium sulfate (Na.sub.2SO.sub.4) 4.38 Magnesium chloride
(MgCl.sub.2.cndot.6H.sub.2O) 11.39 Sodium chloride (NaCl) 24.65
Torque data at 60.degree. C. for w/o lattices comprising 3 wt % of
a phosphorus functional inversion agent or PP are presented in
Table 4 and FIG. 1.
TABLE-US-00005 TABLE 4 Torque data at 60.degree. C. of w/o latices
of Example 1 comprising 3 wt % of a phosphorus functional inversion
agent or PP. Time Torque (g cm) (sec) Control Glycerol PP BPMG HPA
PBTC PSO 0 0.0559 -0.9003 1.8209 0.2899 0.8138 -0.0102 0.0305 20
9.3129 62.2711 6.0933 60.3078 21.5658 64.3819 19.8669 40 32.2011
121.5769 11.0779 133.0414 97.9614 160.7157 99.6195 60 49.9013
156.3670 15.6555 161.5245 132.6497 182.9936 138.4786 80 58.3445
172.8465 21.3521 198.3490 160.4207 185.3333 150.8891 100 64.0411
166.2343 25.0142 212.2854 165.1001 189.6057 159.0271 120 75.0275
169.4895 32.1350 204.5542 173.6450 214.8336 148.1425 140 81.5379
136.7340 34.9833 220.7286 175.3743 214.8336 163.8082 160 88.7604
142.1254 41.5955 231.1045 189.9211 229.6855 164.7237 180 102.9002
149.4497 43.6300 240.0564 193.4814 231.2113 184.2550 200 92.2190
157.9946 47.5972 251.6530 202.2298 226.9389 167.1651 220 104.1209
181.9000 50.9542 259.9945 218.6076 238.0269 193.6137 240 125.5849
151.8911 57.1594 277.0844 222.1680 224.9044 188.0188 260 130.1626
176.8138 58.7870 304.6519 236.7147 267.3238 203.0741 280 142.0644
197.6674 61.9405 328.5573 252.2786 239.6545 217.9260 300 143.8955
208.2469 70.2820 340.1540 277.5065 251.6581 217.2139 320 176.6510
201.0244 70.7906 323.9797 276.0824 239.7563 221.2830 340 159.5612
234.0851 79.9459 318.7917 281.4738 288.1775 240.1021 360 189.6718
220.1487 79.0304 356.7352 299.0723 282.7861 258.6161 380 198.8271
202.3468 78.7252 360.3973 295.3084 316.6606 265.9403 400 218.2566
219.3349 84.7270 361.0077 327.6571 306.1829 283.7423 420 228.6326
232.2540 87.4736 361.8215 314.5345 293.4672 276.9267 440 234.1258
250.5646 86.8632 315.8417 339.6606 292.0431 295.6441 460 246.6380
269.1803 93.5771 322.7590 359.8022 339.1418 296.2545 480 249.0794
288.6098 94.3909 329.3711 319.0104 331.6142 293.8131 500 271.6624
308.7514 94.1874 317.7745 327.4536 350.2299 329.0100 520 297.0937
324.8240 98.4599 316.7572 356.0384 313.4054 308.4615 540 284.3781
293.7978 99.1720 358.0577 340.1693 292.0431 323.4151 560 302.9938
338.0483 102.7323 326.6246 353.2918 318.0847 295.3389 580 284.6832
344.0501 102.8341 310.3485 321.4518 324.1882 323.8220 600 282.5470
293.2892 112.8031 321.6400 330.2002 334.2590 306.4270 620 314.4887
299.0875 114.2273 346.0541 330.2002 311.5743 326.7721 640 327.2044
326.5533 121.9584 357.0404 315.7552 334.4625 324.9410 660 305.1300
297.3582 124.9084 340.3575 330.8105 288.1775 312.6322 680 275.6297
302.6479 140.0655 348.1903 340.2710 339.0401 319.9565 700 323.0337
308.8531 133.7585 371.2819 319.0104 336.9039 311.6150 720 309.0973
300.0031 116.4653 318.0796 356.6488 293.0603 312.3271 740 307.8766
308.7514 124.9084 368.0267 323.8932 343.6178 317.3116 760 293.8385
307.3273 128.0619 338.1195 307.1086 295.4000 292.2872 780 294.2454
305.3945 133.7585 329.0660 328.5726 324.5951 319.6513 800 286.3108
317.3981 135.7931 341.4764 325.8260 320.5261 288.6251 820 303.9093
294.1030 128.9775 362.0249 320.6380 287.9740 309.9874 840 285.4970
292.9840 149.1191 346.2575 307.5155 328.4607 289.1337 860 321.4060
298.9858 131.3171 318.5883 320.3328 289.8051 298.2890 880 300.9593
302.8514 135.2844 352.9714 285.2376 305.8777 301.5442 900 321.6095
294.0013 137.5224 256.5358 320.5363 315.0330 311.3098 920 289.8712
337.3362 125.1119 321.0297 303.2430 280.9550 285.9802 940 311.7421
307.9376 137.8276 315.2313 305.0741 284.6171 288.3199 960 284.9884
317.0929 137.4207 349.3093 325.0122 283.3964 299.6114 980 290.3798
320.9585 129.0792 348.2920 305.6844 298.1466 263.0920 1000 289.4643
299.9013 124.7050 316.0451 327.1484 278.4119 293.1010 1020 318.2526
291.7633 139.5569 333.2367 350.3418 317.0675 285.7768 1040 280.6142
333.4707 131.4189 334.7626 360.6160 312.5916 287.4044 1060 290.0747
300.9186 146.8811 311.0606 336.2020 313.3036 289.9475 1080 311.9456
279.4545 130.8085 309.0261 313.4155 283.3964 303.9856 1100 305.7404
313.0239 163.1571 343.6127 309.2448 279.8360 272.8577 1120 308.0800
305.9031 148.9156 311.3658 323.7915 300.9949 307.4443 1140 292.7195
278.8442 147.0846 351.7507 326.8433 307.5053 289.5406 1160 312.1490
335.2000 144.9483 340.7644 310.7707 315.7450 287.4044 1180 293.6351
323.2981 142.1000 330.8970 317.0776 269.2566 274.1801 1200 282.2418
316.3808 143.6259 350.2248 333.9640 282.3792 283.4371
The data of Table 4 and FIG. 1 demonstrate that the w/o lattices of
Example 1 comprising 3 wt % of a phosphorus functional inversion
agent invert faster than w/o lattices comprising no inversion agent
(control w/o lattices) and faster than 3 wt % glycerol at
60.degree. C. in 3.5% SSW. The data of Table 4 and FIG. 1 also
demonstrate that the w/o lattices of Example 1 comprising 3 wt % of
a phosphorus functional inversion agent invert to a greater extent
than w/o lattices comprising no inversion agent (control w/o
lattices) and to a greater extent than 3 wt % glycerol at
60.degree. C. in 3.5% SSW. The faster inversion rates and greater
extent of inversion of the w/o lattices comprising a phosphorus
functional inversion agent provide better performance of the
invertible lattices than w/o lattices comprising glycerol under
high stress conditions such as high TDS and elevated
temperature.
The results of Example 3 demonstrate that w/o lattices comprising a
phosphorus functional inversion agent provide improved performance
of the invertible lattices over control w/o lattices and w/o
lattices comprising glycerol under high stress conditions such as
high TDS and high temperature.
Example 4
The surface tension of phosphorus functional inversion agents at
0.5 wt % was measured in a Kruss-K12 processor tensiometer at room
temperature. The tested samples were prepared in deionized water
and were neutralized with NaOH or H.sub.2SO.sub.4. Data is
presented in Table 5 as an average+/-standard deviation (SD) of two
experiments.
TABLE-US-00006 TABLE 5 Surface tension data of phosphorus
functional inversion agents. Inversion Agent or Comparative Surface
Tension (mN/m) SD None (deionized water) 72.13 0.14 Lauric Acid
22.17 0.15 BPMG 66.61 0.17 HPA 61.74 0.13 PBTC 66.27 0.13 PSO 55.41
0.14
The data of Table 5 demonstrate that phosphorus functional
inversion agents do not reduce the surface tension of water or
reduce the surface tension of water by 23% or less. By comparison,
a known surfactant, lauric acid, reduces the surface tension of
water by about 69%.
The invention illustratively disclosed herein can be suitably
practiced in the absence of any element which is not specifically
disclosed herein. Additionally each and every embodiment of the
invention, as described herein, is intended to be used either alone
or in combination with any other embodiment described herein as
well as modifications, equivalents, and alternatives thereof. In
various embodiments, the invention suitably comprises, consists
essentially of, or consists of the elements described herein and
claimed according to the claims. It will be recognized that various
modifications and changes may be made without following the example
embodiments and applications illustrated and described herein, and
without departing from the scope of the claims.
* * * * *
References